CN108223775B - Vehicle emergency braking flameout prevention control system and functional module framework - Google Patents
Vehicle emergency braking flameout prevention control system and functional module framework Download PDFInfo
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- CN108223775B CN108223775B CN201810010217.9A CN201810010217A CN108223775B CN 108223775 B CN108223775 B CN 108223775B CN 201810010217 A CN201810010217 A CN 201810010217A CN 108223775 B CN108223775 B CN 108223775B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H59/00—Control inputs to control units of change-speed-, or reversing-gearings for conveying rotary motion
- F16H59/74—Inputs being a function of engine parameters
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/02—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/18—Preventing unintentional or unsafe shift, e.g. preventing manual shift from highest gear to reverse gear
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- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Hydraulic Clutches, Magnetic Clutches, Fluid Clutches, And Fluid Joints (AREA)
Abstract
The invention discloses a control system for preventing flameout of a vehicle in emergency braking and a functional module framework, which comprise a transmission control unit TCU, wherein after the vehicle is braked emergently, the transmission control unit TCU divides a separating clutch into a pre-separating clutch and a completely separating clutch.
Description
Technical Field
The invention relates to the field of vehicle emergency braking flameout prevention, in particular to a vehicle emergency braking flameout prevention control system and a functional module framework.
Background
In view of cost, most of the brake switches mounted on the entire vehicle are digital, and if the brake is pressed, the brake signal is 1, and it is impossible to distinguish between heavy pressing and light pressing of the brake. Under the condition of emergency braking of the vehicle, due to the limitation of physical characteristics (such as response time, fastest execution speed and the like) of a clutch execution system, if the clutch is just separated from a completely combined position of the clutch at the clutch separation time calculated according to the slope of the rotating speed of the engine, the engine is dragged to be flamed out due to untimely separation of the clutch, and after the engine is flamed out, the vehicle cannot turn and has no braking effect, so that the safety of drivers and passengers is seriously influenced.
Disclosure of Invention
The invention aims to provide a control system and a functional module framework for preventing flameout in vehicle emergency braking, aiming at solving the problem that the engine flameout possibly occurs when the clutch is not timely separated due to the limitation of the physical characteristics of the clutch execution system under the condition of vehicle emergency braking, and dividing the clutch into two steps of pre-dividing the clutch and completely separating the clutch after the vehicle emergency braking, thereby ensuring that the clutch is separated in enough time and avoiding the flameout of the engine.
The purpose of the invention is realized by adopting the following scheme: a control system with an emergency braking and fire extinguishing prevention function for a vehicle comprises a transmission control unit TCU, wherein the transmission control unit TCU is respectively and electrically connected with a clutch actuating mechanism, an engine control unit ECU, a key switch, a handle position sensor, a clutch position sensor arranged on the clutch actuating mechanism and a vehicle speed sensor arranged on a transmission, the engine control unit ECU is respectively and electrically connected with an engine speed sensor and a brake switch, the engine control unit ECU is used for acquiring signals of the engine speed sensor and the brake switch in real time and transmitting the signals to the transmission control unit TCU, the transmission control unit TCU acquires signals of the key switch and the handle position sensor, signals of the clutch position sensor arranged on the clutch actuating mechanism and signals of the vehicle speed sensor arranged on the transmission in real time, the speed changer control unit TCU is used for calculating the slope of the engine speed according to the engine speed, judging whether the current vehicle state meets the pre-clutch-dividing condition or not according to the engine speed, a brake signal, a key signal, a handle position, a clutch position, the vehicle speed and the slope of the engine speed, and under the condition that all the pre-clutch-dividing conditions are met, the speed changer control unit TCU controls a clutch execution mechanism to push a clutch to perform pre-dividing by a closed-loop position control mode, so that the clutch is separated from a clutch complete combination position to a clutch pre-dividing position; the transmission control unit TCU is used for judging whether the current vehicle state meets the condition of completely separating the clutch or not according to the brake signal, the clutch position and the engine speed slope, and under the condition that all the conditions of completely separating the clutch are met, the transmission control unit TCU controls the clutch actuating mechanism to push the clutch to be completely separated in a closed-loop position mode, so that the clutch is separated from the clutch pre-separating position to the clutch completely separating position.
The pre-clutch dividing condition comprises key electrification, engine operation, handle position D or R, forward gear or reverse gear of the current gear, brake treading, no error of clutch position signals, no fault of a clutch executing motor, low vehicle speed (the vehicle speed is greater than a preset vehicle speed threshold), engine speed slope less than or equal to an engine speed slope threshold L1, the relation between an engine speed slope threshold L1 and a target gear is established in advance and stored in a transmission control unit TCU, and when the pre-clutch dividing time is judged, the transmission control unit TCU obtains a corresponding engine speed slope threshold L1 according to the target gear.
The completely-disengaged clutch condition comprises that the vehicle is under the condition of emergency braking (namely, the brake is pressed down again), the pre-clutch is completed, the gradient of the engine speed is less than or equal to the gradient threshold L2 of the engine speed, the relation between the gradient threshold L2 of the engine speed and a target gear is established in advance and stored in a transmission control unit TCU, and when the time judgment of completely disengaging the clutch is executed, the transmission control unit TCU obtains the corresponding gradient threshold L2 of the engine speed according to the target gear.
The engine speed ramp threshold L1 in the pre-split clutch timing determination condition is greater than the engine speed ramp threshold L2 in the fully disengaged clutch timing determination condition.
Pre-establishing a clutch pre-fractional position deviation PcompensationRelation to target gear and stored in transmission control unit TCU, clutch pre-split position Ppreopen= Clutch Pre-fractional position deviation Pcompensation+ clutch half-engagement point PtouchWhen executing the pre-divided clutch, the transmission control unit TCU obtains the corresponding pre-divided position deviation P of the clutch according to the target gearcompensationThen calculates the corresponding clutch pre-division position Ppreopen。
The transmission control unit TCU judges whether the clutch pre-distribution is completed in real time according to the value of the clutch position sensor, if the clutch position reaches the clutch pre-distribution position within the specified time and is kept for a certain time, the clutch pre-distribution is successful, otherwise, the clutch pre-distribution is failed; and the transmission control unit TCU judges whether complete clutch separation is finished according to the clutch position, if the clutch position reaches the clutch complete separation position within the specified time and is kept for a certain time, the complete clutch separation is successful, otherwise, the complete clutch separation fails. During the execution of the vehicle emergency braking flameout prevention step, if the failure is due to a clutch actuation system failure, the transmission control unit TCU will disable the function until the next key power-up; if the failure is due to a change in driver intent, the transmission control unit TCU will again enter the vehicle emergency brake anti-stall function.
A functional module framework for controlling vehicle emergency braking and fire extinguishment comprises a signal acquisition and processing module, wherein the signal acquisition and processing module is used for acquiring the rotating speed of an engine, a brake signal, a key signal, the position of a handle, the position of a clutch and the speed of the vehicle, and calculating the rotating speed slope of the engine according to the rotating speed of the engine;
the system comprises a pre-clutch timing judgment module, a first clutch position control module and a second clutch position control module, wherein the pre-clutch timing judgment module is used for judging whether the current vehicle state meets the pre-clutch condition or not according to the engine rotating speed, a brake signal, a key signal, a handle position, a clutch position, the vehicle speed and the engine rotating speed slope, and triggering the first clutch position control module under the condition that all the pre-clutch conditions are met;
the first clutch position control module is used for receiving the trigger of the pre-clutch timing judgment module, controlling the clutch execution mechanism to push the clutch to be pre-divided, and separating the clutch from the clutch complete combination position to the clutch pre-division position;
the complete separation clutch timing judgment module is used for judging whether the current vehicle state meets the complete separation clutch condition or not according to the brake signal, the clutch position and the engine rotating speed slope, and triggering the second clutch position control module under the condition that all the complete separation clutch conditions are met;
and the second clutch position control module is used for receiving the trigger of the complete clutch separation timing judgment module, controlling the clutch execution mechanism to push the clutch to be completely separated, and separating the clutch from the clutch pre-separation position to the clutch complete separation position.
The pre-clutch condition comprises key power-on, engine operation, handle position being D or R, current gear being forward gear or reverse gear, brake being pressed, no error of clutch position signal, no fault of clutch executing motor, low vehicle speed (vehicle speed being larger than preset vehicle speed threshold), engine speed gradient being smaller than or equal to engine speed gradient threshold L1, pre-establishing relation between engine speed gradient threshold L1 and target gear or current gear and storing in storage module, when executing pre-clutch timing judgment, pre-clutch timing judgment module obtaining corresponding engine speed gradient threshold L1 according to target gear or current gear, the fully-disengaged clutch condition comprises that vehicle is in emergency brake, pre-clutch is completed and engine speed gradient being smaller than or equal to engine speed gradient threshold L2, the relation between the engine speed slope threshold L2 and the target gear or the current gear is established in advance and stored in the storage module, and when the time judgment of completely separating the clutch is executed, the time judgment module of completely separating the clutch obtains the corresponding engine speed slope threshold L2 according to the target gear or the current gear.
Pre-establishing a clutch pre-fractional position deviation PcompensationThe relation with the target gear or the current gear is stored in a storage module, and the pre-division position P of the clutchpreopen= Clutch Pre-fractional position deviation Pcompensation+ clutch half-engagement point PtouchWhen the pre-divided clutch is executed, the pre-divided clutch timing judgment module obtains the corresponding pre-divided position deviation P of the clutch according to the target gear or the current gearcompensationThen calculates the corresponding clutch pre-division position Ppreopen。
The target gear is the next gear in which the vehicle is to operate, relative to the current gear. The target gear is obtained through a shift line of the vehicle speed and the accelerator. Because the dynamic property of the vehicle is different when the vehicle runs in different gears, if L1, L2 and PcompensationUsing a fixed value may result in inaccurate pre-clutch timing determinations, full clutch disengagement timing determinations, and clutch pre-split positions, thereby resulting in failure to achieve the desired vehicle emergency brake anti-misfire effect.
The clutch position control module controls the clutch execution mechanism to push the clutch to perform pre-separation, the clutch is separated from the clutch complete combination position to the clutch pre-separation position, the clutch position control module judges whether the clutch pre-separation is completed or not according to the clutch position, if the value of the clutch position sensor reaches the clutch pre-separation position and keeps for a certain time within the specified time, the pre-separation of the clutch is successful, otherwise, the pre-separation of the clutch is considered to fail; the clutch position control module controls the clutch actuating mechanism to push the clutch to be completely separated, the clutch is separated from the clutch pre-dividing position to the clutch completely separating position, the clutch position control module judges whether the clutch is completely separated or not in real time according to the value of the clutch position sensor, if the value of the clutch position sensor reaches the clutch completely separating position within the specified time and keeps for a certain time, the clutch is completely separated successfully, otherwise, the clutch is considered to be completely separated and failed.
The signal acquisition and processing module, the pre-clutch timing judgment module, the complete clutch disengagement timing judgment module, the first clutch position control module and the second clutch position control module are arranged in a transmission control unit TCU.
The invention has the advantages that: the invention provides a control system for preventing flameout during vehicle emergency braking and a functional module framework, which comprise a Transmission Control Unit (TCU), wherein an Electronic Control Unit (ECU) acquires signals of an engine speed sensor and a brake switch in real time and transmits the signals to the TCU through a Controller Area Network (CAN) wire, and meanwhile, the TCU also acquires signals of a key switch and a handle position sensor, signals of a clutch position sensor arranged on a clutch actuating mechanism and signals of a vehicle speed sensor arranged on a transmission in real time. The transmission control unit TCU judges whether the pre-clutch condition is met according to signals such as the engine speed, a brake signal, a key signal, a handle position, a clutch position, the vehicle speed, the engine speed slope and the like. Under the condition of meeting all the pre-divided clutch conditions, the TCU closed-loop position controls the action of the clutch actuating mechanism, the clutch actuating mechanism pushes the clutch to be pre-divided, the TCU judges whether the pre-divided clutch is completed or not in real time according to the value of the clutch position sensor, and when the clutch position reaches the pre-divided position of the clutch and is kept for a certain time, the pre-divided clutch is successful. And after the pre-clutch separation is finished, the time for completely separating the clutch is judged. If the slope of the engine speed is less than or equal to the threshold value L2 of the slope of the engine speed, the TCU closed loop position of the transmission control unit controls the action of the clutch actuating mechanism, the clutch actuating mechanism pushes the clutch to be separated, when the position of the clutch reaches the completely separated position of the clutch and is kept for a certain time, the completely separated clutch is successful, and the execution of the emergency braking flameout prevention function of the vehicle is finished. The vehicle is driven in a forward gear or a reverse gear, and after a certain speed is reached, the accelerator is released, and the brake pedal is stepped on to realize emergency braking. In order to solve the flameout risk under the condition of vehicle emergency braking, after the vehicle emergency braking, the separation clutch is divided into two steps of a pre-separation clutch and a complete separation clutch. Firstly, determining the time of pre-dividing a clutch according to conditions such as the rotating speed slope of an engine, braking and the like, and separating the clutch from a clutch complete combination position to a clutch pre-dividing position in advance; and then, the time for completely separating the clutch is determined according to the slope of the rotating speed of the engine, and the clutch starts to separate from the pre-dividing position of the clutch, so that enough time is ensured for separating the clutch, and the engine is prevented from stalling. The invention identifies heavy treading or light treading brake according to the rotating speed slope of the engine, and determines the clutch separation time, under the condition of vehicle braking, when the rotating speed slope of the engine is less than a set threshold, the driver is considered to be heavy braking.
Interpretation of terms
A transmission control unit: TCU (Transmission Control Unit)
An engine control unit: ECU (Engine Control Unit)
Controller area network: CAN (controller Aera network)
The closed-loop position control refers to position control with feedback, specifically refers to adjusting the duty ratio of an output execution motor according to the deviation between the actual position and the target position, wherein the larger the deviation is, the larger the duty ratio of the execution motor is, and the smaller the deviation is, the smaller the duty ratio of the execution motor is.
The duty cycle is the proportion of the time of energization to the total time within a pulse cycle.
The clutch half-engagement point is the clutch position at which the power output by the vehicle just overcomes the vehicle's resistance.
The fully disengaged clutch position refers to the clutch position when the engine is completely disconnected from the transmission power transmission.
Drawings
FIG. 1 is a schematic diagram of the system of the present invention;
fig. 2 is a flowchart of a control method for preventing flameout of a vehicle in emergency braking according to the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative only and should not be construed as limiting the invention.
As shown in FIG. 1, a control system for preventing flameout in emergency braking of a vehicle comprises a transmission control unit TCU, wherein the transmission control unit TCU is respectively electrically connected with a clutch actuating mechanism, an engine control unit ECU, a key switch, a handle position sensor, a clutch position sensor arranged on the clutch actuating mechanism and a vehicle speed sensor arranged on a transmission, the engine control unit ECU is respectively electrically connected with an engine speed sensor and a brake switch, the engine control unit ECU is used for acquiring signals of the engine speed sensor and the brake switch in real time and transmitting the signals to the transmission control unit TCU through a CAN (controller area network) line, the transmission control unit TCU acquires signals of the key switch and the handle position sensor, signals of the clutch position sensor arranged on the clutch actuating mechanism and signals of the vehicle speed sensor arranged on the transmission in real time, the speed changer control unit TCU is used for calculating the slope of the engine speed according to the engine speed, judging whether the current vehicle state meets the pre-clutch-dividing condition or not according to the engine speed, a brake signal, a key signal, a handle position, a clutch position, the vehicle speed and the slope of the engine speed, and under the condition that all the pre-clutch-dividing conditions are met, the speed changer control unit TCU controls a clutch execution mechanism to push a clutch to perform pre-dividing by a closed-loop position control mode, so that the clutch is separated from a clutch complete combination position to a clutch pre-dividing position; the transmission control unit TCU is used for judging whether the current vehicle state meets the condition of completely separating the clutch or not according to the brake signal, the clutch position and the engine speed slope, and under the condition that all the conditions of completely separating the clutch are met, the transmission control unit TCU controls the clutch actuating mechanism to push the clutch to be completely separated in a closed-loop position mode, so that the clutch is separated from the clutch pre-separating position to the clutch completely separating position.
And the TCU differentiates the engine speed according to the engine speed to obtain the engine speed slope. The engine speed slope is calculated every five cycles (one cycle means 10 milliseconds) in the embodiment, and the specific calculation cycle is adjusted according to actual conditions.
The pre-clutch dividing condition comprises key electrification, engine operation, handle position D or R, forward gear or reverse gear of the current gear, brake treading, no error of clutch position signals, no fault of a clutch executing motor, low vehicle speed (the vehicle speed is greater than a preset vehicle speed threshold), engine speed slope less than or equal to an engine speed slope threshold L1, the relation between an engine speed slope threshold L1 and a target gear is established in advance and stored in a transmission control unit TCU, and when the pre-clutch dividing time is judged, the transmission control unit TCU obtains a corresponding engine speed slope threshold L1 according to the target gear.
The completely-disengaged clutch condition comprises that the vehicle is in emergency braking, the pre-divided clutch is completed, and the engine speed gradient is less than or equal to an engine speed gradient threshold L2, the relationship between the engine speed gradient threshold L2 and a target gear is established in advance and stored in a Transmission Control Unit (TCU), and when the completely-disengaged clutch timing judgment is executed, the Transmission Control Unit (TCU) obtains a corresponding engine speed gradient threshold L2 according to the target gear.
Pre-establishing a clutch pre-fractional position deviation PcompensationRelation to target gear and stored in transmission control unit TCU, clutch pre-split position Ppreopen= Clutch Pre-fractional position deviation Pcompensation+ clutch half-engagement point PtouchWhen executing the pre-divided clutch, the transmission control unit TCU obtains the corresponding pre-divided position deviation P of the clutch according to the target gearcompensationThen calculates the corresponding clutch pre-division position Ppreopen。
The transmission control unit TCU judges whether the clutch is completely separated or not according to the position of the clutch, if the position of the clutch reaches the pre-separating position of the clutch and keeps for a certain time within the specified time, the pre-separating of the clutch is successful, otherwise, the pre-separating of the clutch fails, the transmission control unit TCU judges whether the clutch is completely separated or not according to the position of the clutch, if the position of the clutch reaches the completely separating position of the clutch and keeps for a certain time within the specified time, the completely separating of the clutch is successful, otherwise, the completely separating of the clutch fails. During the execution of the vehicle emergency braking flameout prevention step, if the failure is due to a clutch actuation system failure, the transmission control unit TCU will disable the function until the next key power-up; if the failure is due to a change in driver intent, the transmission control unit TCU will again enter the vehicle emergency brake anti-stall function.
A functional module framework for controlling vehicle emergency braking and fire extinguishment comprises a signal acquisition and processing module, wherein the signal acquisition and processing module is used for acquiring the rotating speed of an engine, a brake signal, a key signal, the position of a handle, the position of a clutch and the speed of the vehicle, and calculating the rotating speed slope of the engine according to the rotating speed of the engine;
the system comprises a pre-clutch timing judgment module, a first clutch position control module and a second clutch position control module, wherein the pre-clutch timing judgment module is used for judging whether the current vehicle state meets the pre-clutch condition or not according to the engine rotating speed, a brake signal, a key signal, a handle position, a clutch position, the vehicle speed and the engine rotating speed slope, and triggering the first clutch position control module under the condition that all the pre-clutch conditions are met;
the first clutch position control module is used for receiving the trigger of the pre-clutch timing judgment module, controlling the clutch execution mechanism to push the clutch to be pre-divided, and separating the clutch from the clutch complete combination position to the clutch pre-division position;
the complete separation clutch timing judgment module is used for judging whether the current vehicle state meets the complete separation clutch condition or not according to the brake signal, the clutch position and the engine rotating speed slope, and triggering the second clutch position control module under the condition that all the complete separation clutch conditions are met;
and the second clutch position control module is used for receiving the trigger of the complete clutch separation timing judgment module, controlling the clutch execution mechanism to push the clutch to be completely separated, and separating the clutch from the clutch pre-separation position to the clutch complete separation position.
The pre-clutch condition comprises key power-on, engine operation, handle position being D or R, current gear being forward gear or reverse gear, brake being pressed, no error of clutch position signal, no fault of clutch executing motor, low vehicle speed (vehicle speed being larger than preset vehicle speed threshold), engine speed gradient being smaller than or equal to engine speed gradient threshold L1, pre-establishing relation between engine speed gradient threshold L1 and target gear and storing in storage module, when executing pre-clutch timing judgment, pre-clutch timing judgment module obtaining corresponding engine speed gradient threshold L1 according to target gear, the fully-disengaged clutch condition comprises that vehicle is in emergency braking, pre-clutch is completed and engine speed gradient being smaller than or equal to engine speed gradient threshold L2, pre-establishing relation between engine speed gradient threshold L2 and target gear and storing in storage module, the fully disengaged clutch timing determination module obtains a corresponding engine speed ramp rate threshold L2 based on the target gear when performing a fully disengaged clutch timing determination.
Pre-establishing a clutch pre-fractional position deviation PcompensationIn relation to the target gear and stored in a memory module, the clutch pre-set position Ppreopen= Clutch Pre-fractional position deviation Pcompensation+ clutch half-engagement point PtouchWhen the pre-divided clutch is executed, the pre-divided clutch timing judgment module obtains the corresponding pre-divided position deviation P of the clutch according to the target gearcompensationThen calculates the corresponding clutch pre-division position Ppreopen。
The clutch position control module controls the clutch execution mechanism to push the clutch to pre-divide by a closed loop position, the clutch is separated from a clutch complete combination position to a clutch pre-division position, the clutch position control module judges whether the pre-division of the clutch is completed or not according to the clutch position, if the clutch position reaches the clutch pre-division position and keeps a certain time within a specified time, the pre-division of the clutch is successful, otherwise, the pre-division of the clutch fails; the clutch position control module controls the clutch execution mechanism to push the clutch to be completely separated, the clutch is separated from the clutch pre-dividing position to the clutch completely separating position, the clutch position control module judges whether the completely separating clutch is completed or not according to the clutch position, if the clutch position reaches the clutch completely separating position within the specified time and keeps the specified time, the completely separating clutch is successful, otherwise, the completely separating clutch fails.
The signal acquisition and processing module, the pre-clutch timing judgment module, the complete clutch disengagement timing judgment module, the first clutch position control module and the second clutch position control module are arranged in a transmission control unit TCU.
As shown in fig. 2, a control method for preventing flameout of a vehicle in emergency braking comprises the following steps:
the first step is as follows: the key of the vehicle is electrified, the engine is started, and the vehicle runs in a reverse gear or a forward gear;
the second step is that: and (3) judging the timing of the pre-divided clutch according to the following conditions:
a) powering on the key;
b) running the engine;
c) the handle position is "D" or "R";
d) the current gear is a forward gear or a reverse gear;
e) the clutch position signal is error free;
f) the clutch executing motor has no fault;
g) stepping down a brake;
h) the vehicle speed is not low (the vehicle speed is greater than a set vehicle speed threshold, for example, the vehicle speed threshold is set to 5 km/h, and the vehicle speed threshold is determined by calibration of the vehicle and is not limited to 5 km/h). Due to the fact that vehicle dynamics are low when the vehicle speed is low, the calculated flameout preventing time of the vehicle in emergency braking is inaccurate.
i) The engine speed ramp rate is less than or equal to the engine speed ramp rate threshold L1 (revolutions per minute);
the relation between the engine speed slope threshold value L1 and the target gear (namely, the two-dimensional table 1) is established in advance and stored in the transmission control unit TCU, and when the pre-clutch timing judgment step is executed, the transmission control unit TCU checks the two-dimensional table 1 according to the target gear to obtain the corresponding engine speed slope threshold value L1, namely, under the condition of emergency braking of the vehicle, the engine speed slope threshold values L1 of the pre-clutch of each gear can be different.
The relationship between the engine speed slope threshold L1 and the target gear of the present embodiment is determined by calibration of the vehicle, making the pre-split clutch timing more accurate. If the pre-distribution time of the clutch is too early, the sliding friction time of the clutch can be increased, and the service life of the clutch is reduced; too late a clutch pre-dispense time can cause the clutch to completely disengage in time resulting in engine stall. The relationship between the engine speed slope threshold L1 and the target gear (i.e., two-dimensional table 1) previously established in the present embodiment is shown in table 1:
| target gear | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| L1(rpm) | -40 | -40 | -45 | -50 | -50 | -50 | -50 | -40 |
TABLE 1
For example: if the target gear is 3, then looking up table 1 yields an engine speed slope threshold L1 of-45.
The invention can increase the pre-divided clutch condition according to the actual condition of the matched vehicle, and is not limited to the condition.
And if all the conditions of the pre-clutch are met, jumping to the third step, and if not, continuously executing the step of judging the time of the pre-clutch.
The third step: the pre-dividing clutch: TCU closed loop position control pre-split clutch to clutch pre-split position PpreopenIf the clutch position reaches the clutch pre-split position P within a specified time (e.g., 1 second)preopenAnd keeping the time for a certain time (such as 30 milliseconds), then the pre-dividing clutch is successful, and the step four is jumped, otherwise, the pre-dividing clutch is failed, and the step six is jumped.
Pre-establishing a clutch pre-fractional position deviation PcompensationRelation to target gear and stored in transmission control unit TCU, clutch pre-split position Ppreopen= Clutch Pre-fractional position deviation Pcompensation+ clutch half-engagement point PtouchWhen the pre-clutch-dividing step is executed, the transmission control unit TCU obtains the corresponding pre-divided position deviation P of the clutch according to the target gearcompensationThen calculate the corresponding distanceCombiner pre-division position Ppreopen。
Clutch pre-fractional position offset P of the inventioncompensationThe relation with the target gear is determined by calibrating the vehicle, so that the pre-division position of the clutch is more accurate. If the pre-distribution position of the clutch is inaccurate, the clutch can be completely separated out in time, so that an engine is flamed out, the sliding friction of the clutch can be too large, the service life of the clutch is shortened, and the driving comfort is reduced.
The embodiment pre-established clutch pre-fractional position deviation PcompensationThe relationship to the target gear (i.e., two-dimensional table 2) is shown in table 2:
| target gear | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| Pcompensation(mV) | 50 | 55 | 60 | 70 | 70 | 70 | 70 | 50 |
TABLE 2
For example: if the target gear is 3, looking up table 3 to obtain the pre-divided position deviation P of the clutchcompensationIs 60.
The fourth step: and (3) judging the time when the pre-divided clutch is completely separated: if the vehicle is in an emergency braking situation, i.e. the brakes are applied, and the engine speed slope is less than or equal to the engine speed slope threshold L2 (rpm), then the fifth step is skipped, otherwise the step is continued.
The relationship between the engine speed slope threshold L2 and the target gear (i.e. two-dimensional table 3) is established in advance and stored in the transmission control unit TCU, and when the determination step of the timing of the completely disengaged clutch is executed, the transmission control unit TCU looks up the two-dimensional table 3 according to the target gear to obtain the corresponding engine speed slope threshold L2, that is, the engine speed slope threshold L2 of the completely disengaged clutch of each gear may be different in the case of emergency braking of the vehicle.
The relationship between the engine speed slope threshold L2 and the target gear is determined by vehicle calibration, so that the complete clutch disengagement timing is more accurate. If the clutch is fully disengaged too soon, which may result in the vehicle not being able to decelerate using engine back-traction, and too late a full clutch disengagement may result in the clutch not being disengaged in time, which may result in engine stall. The relationship between the engine speed slope threshold L2 and the target gear (i.e., the two-dimensional table 3) previously established in the present embodiment is shown in table 3:
| target gear | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| L2(rpm) | -80 | -80 | -90 | -100 | -100 | -100 | -100 | -80 |
TABLE 3
For example: if the target gear is 3, then looking up table 3 yields an engine speed slope L2 of-90.
The fifth step: completely disengaging the clutch: the TCU closed loop position controls the clutch to disengage to a fully disengaged clutch position, and if the clutch position reaches the fully disengaged clutch position within a specified time (e.g., 2 seconds) and remains at that position for a certain amount of time (e.g., 50 milliseconds), then the fully disengaged clutch is successful and the seventh step is skipped, otherwise the fully disengaged clutch fails and the sixth step is skipped.
6) Failure: during the execution of the vehicle emergency braking flameout prevention step, if the failure is due to a clutch actuation system failure, the transmission control unit TCU will disable the function until the next key power-up; if the failure is due to a change in driver intent, a jump is made to the first step.
7) The success is as follows: in the event of a change in the driver's intention, the transmission control unit TCU again jumps to the first step.
The invention relates to a pre-clutch timing judgment and pre-clutch distribution in the vehicle emergency braking flameout prevention function control process, which is extremely important and can effectively solve the problem of engine flameout caused by untimely clutch separation due to the limitation of the physical characteristics of a clutch execution system.
The above is a detailed description of the present technical solution, it should be understood that due to the limitations of the words and the diversity of the technical solutions, a person skilled in the art can implement the technical solution by using the words, syntax or other equivalent alternatives of the technical solution, and therefore, such alternatives should be considered as being within the scope of the present application.
Claims (9)
1. The utility model provides a vehicle emergency braking prevents flameout control system which characterized in that: the speed changer control unit TCU is respectively electrically connected with a clutch actuating mechanism, an engine control unit ECU, a key switch, a handle position sensor, a clutch position sensor arranged on the clutch actuating mechanism and a vehicle speed sensor arranged on the speed changer, the engine control unit ECU is respectively electrically connected with an engine speed sensor and a brake switch, the engine control unit ECU is used for acquiring signals of the engine speed sensor and the brake switch in real time and transmitting the signals to the speed changer control unit TCU, the speed changer control unit TCU acquires signals of the key switch and the handle position sensor, signals of the clutch position sensor arranged on the clutch actuating mechanism and signals of the vehicle speed sensor arranged on the speed changer in real time, and the speed changer control unit TCU is used for controlling the speed of the vehicle according to the rotating speed of the engine, calculating the slope of the rotation speed of the engine, wherein the transmission control unit TCU is used for identifying heavy stepping or light stepping on the brake according to the slope of the rotation speed of the engine and determining the time for separating the clutch; the speed changer control unit TCU is used for judging whether the current vehicle state meets the pre-clutch-dividing condition or not according to the engine speed, the brake signal, the key signal, the handle position, the clutch position, the vehicle speed and the engine speed slope, the pre-clutch distribution condition comprises key electrification, engine operation, handle position D or R, forward gear or reverse gear of the current gear, brake treading, no error of a clutch position signal, no fault of a clutch executing motor, vehicle speed greater than a preset vehicle speed threshold value, engine speed gradient less than or equal to an engine speed gradient threshold value L1, under the condition that all pre-divided clutch conditions are met, the transmission control unit TCU controls a clutch actuator to push a clutch to be pre-divided in a closed-loop position control mode, and the clutch is separated from a clutch complete combination position to a clutch pre-division position; the transmission control unit TCU is used for judging whether the current vehicle state meets a complete separation clutch condition according to a brake signal, a clutch position and an engine speed slope, wherein the complete separation clutch condition comprises that the vehicle is in emergency braking, a pre-separation clutch is completed and the engine speed slope is less than or equal to an engine speed slope threshold L2, the engine speed slope threshold L1 in the pre-separation clutch timing judgment condition is larger than the engine speed slope threshold L2 in the complete separation clutch timing judgment condition, and under the condition that all the complete separation clutch conditions are met, the transmission control unit TCU controls a clutch execution mechanism to push the clutch to be completely separated, and the clutch is separated from the clutch pre-separation position to the clutch complete separation position.
2. The system of claim 1, wherein: the method comprises the steps that the relation between an engine speed slope threshold value L1 and a target gear or a current gear is established in advance and stored in a transmission control unit TCU, and when the time judgment of a pre-clutch is executed, the transmission control unit TCU obtains a corresponding engine speed slope threshold value L1 according to the target gear or the current gear; the relation between the engine speed slope threshold value L2 and the target gear or the current gear is established in advance and stored in the transmission control unit TCU, and when the time for completely disengaging the clutch is judged, the transmission control unit TCU obtains the corresponding engine speed slope threshold value L2 according to the target gear or the current gear.
3. The system of claim 1, wherein: the method comprises the steps that the relation between clutch pre-divided position deviation Pdemand and a target gear or a current gear is established in advance and stored in a transmission control unit TCU, clutch pre-divided position P pre = clutch pre-divided position deviation P demand + clutch half-combination point P touch, and when the pre-divided clutch is executed, the transmission control unit TCU obtains a corresponding clutch according to the target gear or the current gear
The pre-split position deviation P compensation is then calculated, and the corresponding pre-split clutch position P preapen is calculated.
4. The system of claim 1, wherein: the transmission control unit TCU judges whether the pre-dividing of the clutch is finished according to the position of the clutch, if the position of the clutch reaches the pre-dividing position of the clutch and keeps for a certain time within the specified time, the pre-dividing of the clutch is successful, otherwise, the pre-dividing of the clutch fails, the transmission control unit TCU judges whether the complete separation of the clutch is finished in real time according to the position of the clutch, if the position of the clutch reaches the complete separation position of the clutch and keeps for a certain time within the specified time, the complete separation of the clutch is successful, otherwise, the complete separation of the clutch fails, and when the failure occurs in the execution process of the emergency braking and flameout prevention function of the vehicle or the driver changes the driving intention, the transmission control unit TCU quits the execution of the emergency braking and flameout prevention function of the vehicle.
5. A functional module framework for vehicle emergency braking anti-flameout control is characterized in that: the system comprises a signal acquisition and processing module, a signal acquisition and processing module and a control module, wherein the signal acquisition and processing module is used for acquiring the rotating speed of an engine, a brake signal, a key signal, a handle position, a clutch position and the speed of the vehicle, and calculating the slope of the rotating speed of the engine according to the rotating speed of the engine;
the system comprises a pre-clutch timing judgment module, a first clutch position control module and a second clutch timing control module, wherein the pre-clutch timing judgment module is used for judging whether the current vehicle state meets a pre-clutch dividing condition or not according to the engine rotating speed, a brake signal, a key signal, a handle position, a clutch position, the vehicle speed and the engine rotating speed slope, the pre-clutch dividing condition comprises key electrification, engine running, the handle position is D or R, the current gear is a forward gear or a reverse gear, brake treading is performed, the clutch position signal is not wrong, a clutch execution motor is not failed, the vehicle speed is greater than a preset vehicle speed threshold, the engine rotating speed slope is less than or equal to an engine rotating speed slope threshold L1, and the first clutch position control module is triggered under the condition that all the pre-clutch dividing conditions are;
the first clutch position control module is used for receiving the trigger of the pre-clutch timing judgment module, controlling the clutch execution mechanism to push the clutch to be pre-divided, and separating the clutch from the clutch complete combination position to the clutch pre-division position;
a complete separation clutch timing judgment module, which is used for judging whether the current vehicle state meets the complete separation clutch condition according to a brake signal, a clutch position and an engine speed slope, wherein the complete separation clutch condition comprises that the vehicle is under the condition of emergency braking, a pre-separation clutch is completed and the engine speed slope exceeds an engine speed slope threshold L2, the engine speed slope threshold L1 in the pre-separation clutch timing judgment condition is smaller than the engine speed slope threshold L2 in the complete separation clutch timing judgment condition, and a second clutch position control module is triggered under the condition that all the complete separation clutch conditions are met;
and the second clutch position control module is used for receiving the trigger of the complete clutch separation timing judgment module, controlling the clutch execution mechanism to push the clutch to be completely separated, and separating the clutch from the clutch pre-separation position to the clutch complete separation position.
6. The functional module framework of claim 5, wherein: the method comprises the steps that the relation between an engine speed slope threshold value L1 and a target gear or a current gear is established in advance and stored in a storage module, when pre-clutch timing judgment is carried out, the pre-clutch timing judgment module obtains a corresponding engine speed slope threshold value L1 according to the target gear or the current gear, the relation between an engine speed slope threshold value L2 and the target gear or the current gear is established in advance and stored in the storage module, and when complete clutch disengagement timing judgment is carried out, the complete clutch disengagement timing judgment module obtains a corresponding engine speed slope threshold value L2 according to the target gear or the current gear.
7. The functional module framework of claim 5, wherein: the method comprises the steps that the relation between a clutch pre-dividing position deviation Ptouch and a target gear or a current gear is established in advance and stored in a storage module, the clutch pre-dividing position Ptouch = the clutch pre-dividing position deviation Ptouch + a clutch half-joint point Ptouch, when a pre-dividing clutch is executed, a pre-dividing clutch timing judgment module obtains the corresponding clutch pre-dividing position deviation Ptouch according to the target gear or the current gear, and then the corresponding clutch pre-dividing position Ptouch is calculated.
8. The functional module framework of claim 5, wherein: the clutch position control module controls the clutch actuator to push the clutch to perform presorting, the clutch is separated from the clutch complete combination position to the clutch presorting position, the clutch position control module judges whether the clutch presorting is completed in real time according to the value of the clutch position sensor, if the value of the clutch position sensor reaches the clutch presorting position and keeps for a certain time within the specified time, the clutch presorting is successful, otherwise, the clutch presorting fails; the clutch position control module controls the clutch actuating mechanism to push the clutch to be completely separated, the clutch is separated from the clutch pre-dividing position to the clutch completely separating position, the clutch position control module judges whether the completely separating clutch is completed or not in real time according to the value of the clutch position sensor, if the clutch position reaches the clutch completely separating position within the specified time and keeps for a certain time, the completely separating clutch is successful, otherwise, the completely separating clutch fails.
9. The functional module framework of claim 5, wherein: the signal acquisition and processing module, the pre-clutch timing judgment module, the complete clutch disengagement timing judgment module, the first clutch position control module and the second clutch position control module are arranged in a transmission control unit TCU.
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| CN110469598B (en) * | 2019-08-21 | 2020-10-20 | 安徽江淮汽车集团股份有限公司 | Clutch pressure control method and device, electronic equipment and storage medium |
| CN110816515A (en) * | 2019-09-30 | 2020-02-21 | 潍柴动力股份有限公司 | Vehicle flameout prevention control method and vehicle flameout prevention control device |
| CN112572396A (en) * | 2020-12-11 | 2021-03-30 | 潍柴动力股份有限公司 | Manual transmission vehicle AEBS control method, device and system |
| CN112727611B (en) * | 2020-12-23 | 2022-07-19 | 重庆青山工业有限责任公司 | Control method for preventing engine stall of automobile traction control system |
| CN113844259A (en) * | 2021-09-28 | 2021-12-28 | 武汉未来幻影科技有限公司 | Manual gear vehicle braking auxiliary control system, method and device |
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